Europe’s Solar Season Is Getting More Intense and Disruptive

(Bloomberg) -- Europe’s solar energy season is getting longer and more intense, threatening to disrupt markets and overwhelm grids with a glut of cheap power.

Solar energy production surges in April as longer days combine with sunnier weather, while the warmer conditions also curb household heating demand. Swaths of new solar capacity are generating a flood of electricity that can drive power prices below zero, eating into the profits of renewable-energy producers and scaring off some investors.

Negative prices happen when supply outpaces demand, though very few consumers — usually those with a special tariff for electric vehicle charging — can take advantage of the free power. That excess can be counterbalanced either by boosting demand or by storing the electricity. Some new solar farms are built with a battery to head off this problem but more investment is needed.

“The rise in negative prices — and price spikes at other times — is a blaring signal for investment in system flexibility,” said Chris Rosslowe, senior energy and climate data analyst at the think tank Ember.

That signal is set to get louder as the European Union is projected to connect a record amount of new solar panels and farms to the grid this year and next, according to BNEF data.

On a daily basis, there’s also a mismatch between surging solar supply and demand, with the latter peaking during the early evening, just as generation begins to drop. With solar capacity growing to meet decarbonization targets, Europe has been wrestling to find ways to use cheap electricity during the day while avoiding falling back on fossil fuels in the evening.

Periods of sunny weather in March boosted solar output beyond demand, sending prices into negative territory. Revenue from solar energy production in Germany also tanked and is expected to fall further in April, according to a BNEF analysis. 

The gap between prices paid to solar generators and the baseload power price is expected to continue widening, which could hurt the companies building and operating solar farms, according to BNEF analysts Mbongeni Dube and Kesavarthiniy Savarimuthu. 

Low prices are also discouraging some investors from backing new renewable projects, which threatens to derail Europe’s 2030 clean energy targets. 

The duration of negative pricing has increased in recent years and in 2024 it spread to countries such as Bulgaria, Greece and Spain for the first time, according to the European Agency for the Cooperation of Energy Regulators.

“This frequency of negative pricing is likely to continue with the increase in solar generation,” said agency spokeswoman Ilaria Bellacci.

Subsidies that incentivize renewable producers to keep generating even when prices dip below zero need to be restructured, the agency said.

Ember’s Rosslowe said new investment to make Europe’s energy grid more flexible will help stabilize prices as more renewable projects ramp up. One potential remedy is increased battery storage, which would allow operators to take electricity off the grid at times of surplus and tap that supply when demand is high, he said.

Grid Expansion

Negative pricing could also be curbed by expanding Europe’s grid, according to Rosslowe. For the moment, capacity is being been throttled by slow planning and bottlenecks in electricity connections between different regions.

“Negative prices are telling us we need more routes to use abundant solar power,” he said.

Adding more grid connections will also help to ease other costs, such as paying operators to switch off turbines. In 2024, the UK spent more than £1 billion on “congestion costs,” despite a record year for wind output. 

Weather patterns in Europe this spring are pointing to strong solar energy production, after record-breaking sunshine in the UK last month.

A new BNEF analysis published Wednesday expects booming solar energy generation in April as cloud cover improves, including a 75% month-on-month increase in Spain. The report also predicts power demand to drop, despite a potential cold front forecast to bring unseasonably cool temperatures and a jump in heating demand in some areas.

However, not everyone thinks surging of solar energy will translate into more negative pricing. 

Tim Partridge, who heads energy trading at Manchester’s LG Energy Group Ltd., says seasonal maintenance at Nordic nuclear plants and gas fields in Norway may offset part of the excess solar power.

“Negative pricing may be less prevalent than hoped for,” he said.

Explainer: Why Power Prices Can Go Negative and What It Means

(Updates with BNEF solar outlook in 18th paragraph. An earlier version of this story corrected the subhead of the first chart)

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